Drainage catheter having an expandable retention member

ABSTRACT

A drainage catheter is adapted to drain fluid from the body cavity through a body conduit and includes an elongate tube and a retention member disposed at the distal end of the elongate tube. The retention member is adapted for movement between a low-profile state facilitating insertion of the catheter and a high-profile state facilitating retention of the catheter in its operative position. A woven mesh forms at least a portion of one of the tube and the retention member. The woven mesh can be formed of filaments heat-settable so that the catheter automatically moves to the high-profile state. Insertion of the catheter can be facilitated using a stylet which can be removed after insertion to permit the catheter to automatically return to its high-profile state.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.10/521,368 filed on Jan. 12, 2005, which is a 371 of InternationalApplication No. PCT/US03/21756 filed on Jul. 11, 2003, which claimsbenefit of U.S. Provisional Patent Application No. 60/396,225, filed onJul. 16, 2002, the disclosure of which is hereby incorporated byreference as if set forth in full herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention generally relates to medical devices and, morespecifically, to drainage catheters adapted for use in draining a fluidfrom a body cavity.

2. Discussion of the Prior Art

Urinary drainage catheters are used to provide an outlet for the urinarybladder when the urethra is compromised or obstructed, such as when thepatient is incapable of controlling the urinary system due to sedationor lack of mental capacity. A typical urinary catheter is the Foleycatheter, which is a thick-walled rubber tube with an inflatable balloonnear its distal end. The Foley catheter is inserted through the urethraand into the bladder cavity. When disposed, the balloon is inflatedwithin the bladder cavity to a size that prevents the distal end frompassing back through the bladder neck.

There are several disadvantages associated with the Foley catheter, themost significant of which is patient discomfort due to the constructionof the catheter. The typical diameter of a Foley catheter is one-quarterinch or more. This size of catheter is difficult to insert and is veryuncomfortable for the patient. Patient frustration sometimes leads toinadvisable patient removal of the catheter, even with the ballooninflated. This of course can be very damaging and traumatic to thepatient. The hard rubber tip of the Foley catheter also contributes topatient discomfort. In particular, as the bladder empties, it collapsesand the hard rubber tip begins to rub against the wall of the bladdercausing irritation.

Thus, there is a need in the art for a drainage catheter that improvespatient comfort during insertion and withdrawal of the catheter.

SUMMARY OF THE INVENTION

A drainage catheter having an elongate tube and a retention memberdisposed at the distal end of the elongate tube. The retention member isadapted for movement between a low-profile state facilitating insertionof the catheter and a high-profile state facilitating retention of thecatheter in a body cavity. The retention member is oval or bulb shapedin the high-profile state and is cylindrical in the low-profile state.This construction of the catheter provides for less traumatic insertionand withdrawal of the catheter. A pusher or stylet is provided tofacilitate insertion of the catheter. The retention member is preferablyformed of a woven mesh that facilitates drainage of fluid into theelongate tube.

These and other features and advantages of the invention will be moreapparent with a description of preferred embodiments and reference tothe following drawings.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a drainage catheter adapted for use in theurinary tract of a patient;

FIGS. 2 a-2 f illustrate different configurations of a drainage catheterin accordance with an embodiment of the invention;

FIGS. 3 a-3 d illustrate different embodiments of the invention formaintaining the position of a retention member in the bladder;

FIGS. 4 a-4 c illustrate different embodiments of a pusher or stylet ofthe invention;

FIGS. 5 a-5 c illustrate different embodiments of a snap-fit mechanismfor deploying the retention member;

FIG. 6 illustrates a mechanism for deploying the retention member andreleasing the suture assembly in a single motion in accordance with anembodiment of the invention; and

FIGS. 7 a-7 d illustrate different embodiments of a mechanism of theinvention for providing fast collapse of the retention member for easycatheter removal.

DESCRIPTION OF PREFERRED EMBODIMENTS AND BEST MODE OF THE INVENTION

Co-pending U.S. patent application Ser. No. 09/598,014 filed Jun. 20,2000, entitled Drainage Catheter, is incorporated herein by reference.

Referring to FIG. 1, a drainage catheter 10 adapted for use in theurinary tract of a patient is illustrated. The urinary tract includes aureter 11 extending in fluid communication between a kidney 12 and abladder 14 having a bladder cavity 15. A urethra 18 begins at a bladderneck 21 and passes outwardly through a prostate 23 and a meatus 25 of apenis 27. When urethra 18 is compromised or obstructed, urine cannotnaturally drain from bladder 14 and it becomes desirable to open urethra18 or otherwise provide a fluid passage from bladder 14 through urethra18 and meatus 25.

Catheter 10 includes an elongate tube 24 having a wall 35 extendingdistally to a retention member 26. Tube 24 extends along an axis 37between a proximal end 39 and a distal end 41. Retention member 26 canbe formed of a mesh. With catheter 10 operatively positioned, urethra 18is opened or otherwise augmented with a passage through tube 24 to drainurine from bladder 14. A drainage conduit 45 can be connected at theproximal end of tube 24 to gather urine in a collection bag 51.

FIGS. 2 a-2 f illustrate different configurations of catheter 10 ingreater detail. Catheter 10 further comprises a hub 22 at the proximalend of tube 24, a stop ledge 36 near a distal end of tube 24 and atleast one hole 38 drilled along the distal end of tube 24 for drainingfluid from bladder 14. Retention member 26 can be formed from filamentsforming a mesh 28 as illustrated in FIG. 2 a. Retention member 26further includes a tethered bushing 32 and a sliding bushing 46. Athrough lumen 34 can be provided at an end of tethered bushing 32,preferably along axis 37. To reduce the profile of retention member 26,the preferred longitudinal cross-section of retention member 26 iscylindrical when collapsed and resembles a bulb when fully deployed asillustrated in FIGS. 2 c and 2 d, respectively.

In particular, during placement of retention member 26 as illustrated inFIG. 2 c, sliding bushing 46 moves toward the proximal end of tube 24causing retention member 26 to compress into a cylindrical configurationin a low-profile state. After placement of retention member 26 inurethra 18, sliding bushing 46 moves toward stop ledge 36 as illustratedin FIG. 2 d so as to expand retention member 26 to its oval or bulbshape for bladder retention in a high-profile state. In other words, theoval or bulb shape profile of retention member 26 will engage with thebladder wall when the catheter is retracted.

In a preferred construction of retention member 26, filaments formingmesh 28 are woven and movable relative to each other. Thischaracteristic enables retention member 26 to be stretched between thelow-profile state and the high-profile state. When the filaments aremade of polyester or some other heat-settable material, mesh 28 can beheat set in the high-profile state such that retention member 26 isbiased to the high-profile configuration. When mesh 28 is stretchedduring placement of retention member 26, the filaments elongateproviding retention member 26 with the low-profile configuration. Thatis, the filaments move to a more parallel relationship with axis 37 asretention member 26 is drawn to the low-profile state having asignificantly reduced cross-section.

Another feature of the invention is it maintains the position ofretention member 26 in bladder 14 even when tube 24 is bent and/orcoiled. Referring to FIGS. 3 a-3 d, at least one suture 40 isoperatively attached to tethered bushing 32 at the tip of the catheterto reduce movement of retention member 26 and to secure retention member26 to the catheter tip even when tube 24 is bent and/or coiled. Inparticular, retention member 26 is secured to catheter 10 by securingone end of suture 40 to tethered bushing 32, running suture 40 along aninner diameter (I.D.) 42 of tube 24, and securing the other end ofsuture 40 near the proximal end of tube 24 as further discussed below.In another embodiment of the invention, a separate tube 44 confiningsuture 40 (see FIG. 3 b) is provided within the I.D. 42 of tube 24. Inyet another embodiment of the invention, suture 40 is confined within alumen 46 that is incorporated into tube 24 as illustrated in FIG. 3 d.

Another feature of the invention is it provides a soft tip catheterallowing for less traumatic interface between the catheter and theureteral cavity. In particular, tethered bushing 32 has a soft tip thatprovides for less traumatic interface between catheter 10 and urethra18. In a preferred embodiment of the invention, soft tip tetheredbushing 32 is molded onto a braided structure or mesh 28 of retentionmember 26. Alternatively, soft tip tethered bushing 32 can be molded andthen attached to retention member 26 by adhesive or with a snap-fitmechanism. An advantage of soft tip tethered bushing 32 is it can resistpuncturing and damaging of the ureteral wall during insertion. Inparticular, soft tip tethered bushing 32 can deflect during placement ofcatheter 10 and enables it to follow the path of least resistance ratherthan puncturing through an obstruction. Soft tip tethered bushing 32 canbe made from CFlex, Kraton, silicone dispersion, Tecoflex, chronothaneFlex or any foreseeable soft material that can be used inside a bodycavity.

FIGS. 4 a-4 c illustrate different embodiments of pusher or stylet 50 ofthe invention for providing ease of insertion and placement of acatheter in a bladder. To provide for ease of insertion and placement ofcatheter 10, tube 24 and retention member 26 need appropriate stiffness.However, patient comfort commands a soft and flexible construction ofthe catheter body and retention member. The present invention achievesthese opposing requirements by providing a pusher or stylet 50 havingproper column strength to facilitate insertion of a catheter having asoft and flexible body and retention member. Stylet 50 comprises ahandle 52 and a body 54 having a tip 56. Handle 52 is inserted incatheter hub 22 so as to run along the center of tube 24 up to thecatheter distal tip. Stylet 50 is preferably straight in order to keepretention member 26 inline with tube 24. Stylet 50 can be made from aplastic tube, a solid rod or a malleable material incorporated within aplastic body. Alternatively, a malleable stylet can be used without theplastic casement.

FIG. 4 b illustrates a curved stylet 50 b having a handle 52 b and acurved body 54 b. Depending on the needs of a procedure and/or apatient's anatomy, a physician can choose between a straight stylet anda curved stylet. Curved stylet 50 b can be used to position retentionmember 26 through more tortuous paths. It is preferable that the stylethandle is operatively removable from the stylet body such that it can beused with either a straight body or a curved body stylet. Similarly, hubmember 22 can be free to move along tube 24. Hub 22 can have an internalconfiguration that mates to an additional feature attached to tube 24.These features mate as a one-way snap-fit assembly. Curved stylet 50 bcan be made from a malleable material that allows a user to shape thestylet in any desired shape, or can be made from a malleable materialincorporated within plastic.

Referring back to FIGS. 2 b-2 d, a preferred method for moving catheter10 to an operative position within urethra 18 and bladder 14 isillustrated. In FIG. 2 b, catheter 10 is illustrated in its normal statewith its proximal end 39 and distal end 40 extending along axis 37. Inan initial step of insertion, stylet 50 is provided with a distal end123 and a proximal end 125. Distal end 123 of stylet 50 can then beinserted into proximal end 39 of catheter 10 and moved distally alongtube 24 into retention member 26 where it contacts distal tip 83 ofcatheter 10. This contact fixes distal end 123 of stylet 50 at distaltip 83 of catheter 10. Grasping proximal end 125 of stylet 50 in onehand and proximal end 39 of catheter 10 in the other hand, these twoends can be moved toward each other as illustrated in FIG. 2 c. Asproximal end 125 advances toward proximal end 39, retention member 26 isdrawn down onto stylet 50. As a result, the enlarged size of retentionmember 26 is drawn down to substantially the same diameter as tube 24.Once catheter 10 is operatively positioned with its distal tip 83 inbladder 14, stylet 50 can be removed thereby permitting retention member26 to expand automatically to its high-profile state as illustrated inFIG. 2 d. This natural axial contraction and radial expansion ofcatheter 10 will automatically move retention member 26 to its enlargedstate. Once catheter 10 is no longer needed for draining bladder 14, itcan be removed with minimal patient discomfort by cutting tube 24 nearits proximal end to collapse retention member 26 as illustrated in FIG.2 e. By cutting tube 24, the suture 40 placed inside tube 24 forsecuring retention member 26 is also cut and, as a result, retentionmember 26 collapses. The collapsed position of retention member 26ensures the lowest profile and easy removal of catheter 10.

FIGS. 5 a-5 c illustrate different embodiments of a one-way snap-fitmechanism that allows a user to activate or deploy retention member 26from outside a patient's body after placement of retention member 26 inbladder 14. Snap-fit mechanism 60 comprises a one-way plug 62 havingsuture 40 incorporated therethrough and a collar 64. Suture 40 is placedwithin inner diameter 42 of tube 24 such that it can be pulled throughcatheter hub 22. Suture 40 can be used to pull plug 62 through collar 64so as to secure and deploy retention member 26 to the high-profile statehaving an oval or bulb shape. In one embodiment of the invention, suture40 can be pulled until plug 62 is secured to collar 64 on hub 22 asillustrated in FIG. 5 a. In another embodiment of the invention, an endof suture 40 can be attached to stylet handle 52 such that stylet 50 canbe pulled to deploy retention member 26 to its bulb shape in thehigh-profile state as illustrated in FIG. 5 b. Once retention member 26has been deployed and suture 40 has been pulled to a proper distance,suture 40 can breakaway allowing for removal of stylet 50. In yetanother embodiment of the invention as illustrated in FIG. 5 c, thesuture end can be attached to a mechanism 66 that snaps into stylethandle 52. Once retention member 26 has been deployed and suture 40 hasbeen pulled to a proper distance, the user can release suture 40 bypulling the mechanism 66 out of stylet handle 52

FIG. 6 illustrates a mechanism for deploying retention member 26 andreleasing a suture assembly in a single motion such as removal of thestylet handle. In one embodiment, the mechanism comprises a housing orcollar 70 attached within tube 24 or on hub 22 for retaining aratcheting member 72. Ratcheting member 72 operates to hold suture 40and has a built in collapsible back end for snap action when pulledthrough collar 70. Ratcheting member 72 slides axially along tube 24pulling on suture 40 until retention member 26 is deployed. Stylethandle 125 comprises a pin 76 and a pair of extensions or snap claws 74operatively attached to an end of ratcheting member 72. As stylet handle125 is being removed from catheter 10, ratcheting member 72 is beingpulled through collar 70 by snap claws 74 to deploy retention member 26.In the same motion of removing stylet handle 125 from catheter 10, snapclaws 74 will come into contact with pin 76, which causes snap claws 74to cam to an open position thereby releasing ratcheting member 72. Anadvantage of the mechanism of the invention is it is utilized as aone-handed push pull mechanism to activate retention member 26. Inanother embodiment of the invention, a rotating mechanism can beincorporated to activate retention member 26. This rotating mechanismcomprises a housing that retains a ratcheting member. The ratchetingmember winds the suture onto itself until retention member 26 isdeployed.

FIGS. 7 a-7 d illustrate different embodiments of a mechanism tocollapse retention member 26 for easy catheter removal. A feature of theinvention is to preload catheter retention member 26 and assist it to acollapsed position after the securing suture 40 is cut. In other words,when the securing suture 40 is cut, retention member 26 immediatelyadvances to a collapsed position. An advantage of the collapsed positionis it ensures the lowest profile of retention member 26 and easy removalof catheter 10. The invention provides a member 80 that can storepotential energy for assisting retention member 26 to a collapsedposition once the securing suture 40 is cut at the distal end of tube24. Member 80 can be made from a metallic or nonmetallic material. Somespecialty material such as memory wire and plastics may also beincorporated to assist retention member 26.

FIG. 7 a illustrates one embodiment of member 80 which comprises one ormore wires 82 connected from the distal end of tube 24 to tetheredbushing 32 of retention member 26. When retention member 26 is deployedto an oval or bulb shape, wire 82 will bend within the inner diameter 86of retention member 26. Bending of wire 82 will store potential energyinto the wire member. This potential energy can then be used to assistretention member 26 to collapse to its low-profile shape once suture 40is cut. In another embodiment of the invention as illustrated in FIG. 7b, a spiral shaped wire such as a spring 88 with a varying number ofcoils can effectively store and release enough force to collapseretention member 26 to its low-profile shape once suture 40 is cut. Inyet another embodiment of the invention as illustrated in FIG. 7 c, acombination of spring and wire such as a coil wire 90 maybe used tofurther take advantage of the potential energy when deploying retentionmember 26. Another device having the ability to store potential energyis a bellows 92 as illustrated in FIG. 7 d. Bellows 92 is made from aseries of convoluted shapes that collapse or contract when retentionmember 26 is deployed and release the stored potential energy oncesuture 40 is cut.

Although the disclosed retention member of the invention has acollapsible oval or bulb shape that facilitates both insertion andwithdrawal of the drainage catheter, it will be apparent that otherretention members having different collapsible shapes also facilitateinsertion and withdrawal of the drainage catheter.

With the wide variety of features and advantages associated with boththe apparatus and method of the present invention, one is cautioned notto restrict the concept merely to the embodiments disclosed, but ratherto determine the scope of the invention only with reference to theclaims.

1. A drainage catheter adapted to drain fluid from a body cavity througha body conduit, comprising: an elongate tube having a proximal end and adistal end, and being sized and configured for insertion into the bodycavity; an expandable retention member disposed at the distal end of theelongate tube and being adapted for movement between a low-profile statefacilitating insertion of the catheter into the body cavity, and anexpanded high-profile state facilitating retention of the distal end ofthe catheter in the body cavity; and a stylet removably insertable intothe elongate tube to facilitate insertion and placement of the catheterin the body cavity.
 2. The drainage catheter of claim 1, wherein theretention member is formed from a plurality of woven filaments, thewoven filaments being permeable by the fluid to facilitate drainage ofthe fluid from the body cavity.
 3. The drainage catheter of claim 2,wherein the woven filaments form a mesh.
 4. The drainage catheter ofclaim 1, wherein said stylet further comprises an elongate body and ahandle disposed along the elongate body.
 5. The drainage catheter ofclaim 4, wherein said elongate tube further comprises a hub sized andconfigured to receive said handle of said inserting stylet.
 6. Thedrainage catheter of claim 1, wherein said stylet is formed from one ofa plastic tube, a solid rod or a malleable material incorporated withinplastic.
 7. The drainage catheter of claim 4, wherein said handle isremovably connected to said elongate body.
 8. The drainage catheter ofclaim 7, wherein said elongate body is one of a straight or a curvedbody stylet.
 9. The drainage catheter of claim 1, further comprisingmeans for deploying the retention member after placement of theretention member in the body cavity.
 10. The drainage catheter of claim9, wherein said deploying means includes a snap-fit mechanism.
 11. Thedrainage catheter of claim 9, wherein said deploying means comprises aone-way plug having a suture incorporated therethrough and a collardisposed at a proximal portion of the elongate tube, said suture beingplaced within the elongate tube and is operable to pull said plugthrough said collar to secure and deploy said retention member to thehigh-profile state.
 12. The drainage catheter of claim 11, wherein anend of said suture is attached to a handle of said stylet.
 13. Adrainage catheter adapted to drain fluid from a body cavity through abody conduit, comprising: an elongate tube having a proximal end and adistal portion, and being sized and configured for insertion into thebody cavity; an expandable retention member disposed at the distalportion of the elongate tube and being adapted for movement between alow-profile state facilitating insertion of the catheter into the bodycavity, and an expanded high-profile state facilitating retention of thedistal end of the catheter in the body cavity; and an energy storingmember disposed at a distal end of the elongate tube and attached to theretention member to assist the retention member to collapse to thelow-profile state.
 14. The drainage catheter of claim 15, wherein theenergy storing member is formed from a metallic material.
 15. Thedrainage catheter of claim 15, wherein the energy storing member isformed from plastic.
 16. The drainage catheter of claim 15, wherein theenergy storing member is a memory wire.
 17. The drainage catheter ofclaim 15, wherein the energy storing member is a spiral shaped wire. 18.The drainage catheter of claim 15, wherein the energy storing member isshaped like a bellows.